This invention relates generally to switches for actuating, or "honking" a vehicle horn and, more particularly, to a horn switch actuated by rocking an air bag module mounted on a steering wheel.
Prior to the mounting of air bags within steering wheel hubs, many different types of horn actuators were used. Many years ago, a horn actuation ring was placed about the steering wheel hub within easy reach of the driver's thumbs. More recently, the horn switch or switches were relocated for actuation by depressing the steering wheel hub. This arrangement allows the driver to simply depress the steering wheel hub at any location to actuate the horn. This central location became so standard that drivers instinctively depress the steering wheel hub when they desire to honk the horn.
Most currently-produced automotive passenger vehicles are manufactured with driver-side air bags as standard equipment. This air bag is included in a module that is usually stored in a compartment within the steering wheel hub beneath a vinyl covering. Upon actuation, the deploying air bag fragments this vinyl covering into cover doors which open to free the air bag. This location of the air bag module and cover doors in the steering wheel hub necessitates switch relocation. Placing the horn actuation switches for easy and reliable accessibility by the driver presents an ergonomic problem.
One solution to this switch placement problem is shown in U.S. Pat. No. 3,819,205--Dunford et al. There, the horn actuation switches are relocated to the four steering wheel hubs, away from the path of air bag deployment. With this placement of the switches so near the steering wheel rim, the opportunity for inadvertent horn actuation is increased. Also, this placement now requires a thoughtful, rather than instinctive, effort to actuate the horn by any driver who has become accustomed to the central steering wheel hub switch location.
Another proposed solution to this problem is illustrated in U.S. Pat. No. 5,058,462--Gaultier, in which the horn actuation switches are mounted in one of the air bag cover doors atop the air bag module. However, placement of the horn actuation switches on top of the air bag module runs the risk that the switches could inadvertently be exploded into the passenger compartment upon air bag deployment, thus creating a hazard.
Yet another proposed solution is related in U.S. Pat. No 4,785,144--Fosnaugh et al. Here, the air bag module is suspended on a plate by four telescoping spring-biased corner posts, which incorporate horn actuation switch contacts. Depressing any portion of the air bag module against the spring bias will close the contacts and blow the horn. Although this four-corner suspension arrangement permits horn actuation by the familiar act of depressing the steering wheel hub, it has been found to be susceptible to involuntary brief horn actuation, known as "chirp", by vibrations when the vehicle encounters rough pavement.
It would be desirable to provide a horn actuation switch arrangement which permits horn actuation by depressing the steering wheel hub, but which avoids involuntary horn chirp.